Emma Watson as Hermione and Daniel Radcliffe as Harry Potter in Harry Potter and the Prisoner of Azkaban. Photograph: Murray Close/AP

Boris Johnson, the mayor of London, today urged Harry Potter fans to lobby author JK Rowling for a theme park in the capital dedicated to the fictional wizard she created.

The mayor used his weekly Daily Telegraph column to express his "jealous irritation" at the fact that Orlando, Florida, is about to become the "official place of pilgrimage for every Harry Potter fan on earth".

Johnson said it would be "utterly mad" to leave it to the Americans "to make money from a great British invention" and is hoping for interest for a similar theme park in London.

A spokesman for Johnson's office at City Hall said the mayor first suggested a Harry Potter theme park in London to Warner Brothers 18 months ago but "the state of Florida beat us to it with an offer were unable to match".

The vast 20-acre theme park will open later this month and is "gonna be huge", according to the London mayor.

Johnson said the "crowning insult" was when his 12-year-old child told him to make preparations to visit Florida as he appealed to children to start lobbying.

He wrote in his column: "I appeal to the children of this country and to their Potter-fiend parents to write to Warner Bros and Universal, and perhaps, even, to the great JK herself. Bring Harry home to Britain – and if you want a site with less rainfall than Rome, with excellent public transport, and strong connections to Harry Potter, I have just the place."

City Hall was unable to confirm reports that the mayor was writing to Warner Bros, which is behind the Wizarding World of Harry Potter along with Universal Studios, in a renewed attempt to urge them to develop a similar theme park in London.

A spokesman for Johnson's office said: "If a business came up with serious plans for a similar theme park for London, the mayor would be interested to hear them."

Johnson quipped that Britain had a knack for inventing things and then someone else "carts it off and makes a killing from it elsewhere".

Wishing the US theme park success well, he went on: "But I cannot conceal my feelings; and the more I think of those millions of beaming kids waving their wands and scampering the Styrofoam turrets of Hogwarts, and the more I think of those millions of poor put-upon parents who must now pay to fly to Orlando and pay to buy wizard hats and wizard cloaks and wizard burgers washed down with wizard meade, the more I grind my teeth in jealous irritation.

"Because the fact is that Harry Potter is not American. He is British. Where is Diagon Alley, where they buy wands and stuff? It is in London, and if you want to get into the Ministry of Magic you disappear down a London telephone box. The train for Hogwarts goes from King's Cross, not Grand Central Station, and what is Harry Potter all about? It is about the ritual and intrigue and dorm-feast excitement of a British boarding school of a kind that you just don't find in America. Hogwarts is a place where children occasionally get cross with each other – not 'mad' – and where the situation is usually saved by a good old British sense of HUMOUR. WITH A U. RIGHT? NOT HUMOR. GOTTIT?"